The Media Inactive Call Detection feature enhances Cisco IOS behavior for disconnecting a call when an inactive condition is detected. The former behavior automatically disconnected inactive calls. The current feature provides more control for managing these calls.

The Media Inactive Call Detection feature enhances Cisco IOS behavior for disconnecting a call when an inactive condition is detected. The former behavior automatically disconnected inactive calls. The current feature provides more control for managing these calls.

Latest revision as of 17:24, 16 October 2012

The Media Inactive Call Detection feature enhances Cisco IOS behavior for disconnecting a call when an inactive condition is detected. The former behavior automatically disconnected inactive calls. The current feature provides more control for managing these calls.

Media Inactive Call Detection Overview

The Media Inactive Call Detection feature detects inactive (silent) H.323 or SIP call-legs on Cisco IOS-based gateways, and reports this situation to the Tcl IVR 2.0 application (which can disconnect the call). When the Media Inactive Call Detection feature is enabled, Cisco IOS software does not automatically disconnect detected inactive calls. Inactivity is defined as no RTP/RTCP packets for a configurable length of time.

The command-line interface enables system administrators to do the following:

Use additional filters to display one or more calls detected and reported as inactive

Manually release a call by entering the called number, the calling number, or the call ID

The Media Inactive Call Detection feature enables a system administrator to view all detected inactive calls that have been reported to the Tcl script. An internal error code (IEC) is generated when an inactive call is requested to be cleared via the CLI command.

Prerequisites for Media Inactive Call Detection

Note:

Before the following step is done, you should set the inactive timer. This can be done using the timer receive-rtcp command in the CLI or it can be set in the script itself using infotag set media_timer_factor.

To enable the Media Inactive Call Detection feature, set the information tag evt_feature_report using media_inactivity type. For example:

infotag set evt_feature_report media inactivity

Restrictions for Media Inactive Call Detection

The Media Inactive Call Detection feature does not change the existing behavior for the default session application and Tcl IVR 1.0 or the existing Tcl IVR 2.0 script behavior that does not request the new feature.

This feature does not support MGCP call legs.

The Media Inactive Call Detection feature works in IP only. This feature does not include PSTN inactive call detection.

This feature supports RTP/RTCP media inactivity detection and notification only on H.323 and SIP basic calls.

Information about Media Inactive Call Detection

This section provides information about the configuration of Media Inactive Call Detection.

Improved Functionality of Media Inactive Call Detection

Legacy Functionality

This functionality is an enhancement to the pre-existing Media Inactivity Timer feature, which enables gateways to monitor and disconnect VoIP calls if no RTCP packets are received within a configurable time period.

The Media Inactivity Timer feature requires the configuration of the Cisco IOS ip rtcp report interval command and the timer receive-rtcp command to enable detection of RTCP packets by the gateway. When these commands are configured, the gateway uses RTCP report detection, rather than RTP packet detection, to determine whether calls on the gateway are still active or should be disconnected.

If no RTCP packets are received in the resulting time period, the call is disconnected.

The ip rtcp report interval command configures the RTCP reporting interval in milliseconds in the range of 1 to 65535. The timer receive-rtcp command configures the multiplier in the range of 2 to 1000. These values can be adjusted depending on network traffic conditions. Under normal conditions, a value of 5000 for the ip rtcp report interval and a value of 5 for the timer receive-rtcp are typical.

Current Functionality

The Media Inactive Call Detection feature offers the following:

The show callactive command indicates that a call has no RTP or RTCP inactivity.

The clear call command offers options so that an inactive call can be released using the called number or calling number. The clear call command has also been enhanced to configure the Q.850 release cause code to be used when the call is released.

Modifications to Information Tags and Internal Error Codes

This feature includes modifications to two information tags, the addition of two information tags, and an internal error code:

evt_feature_report

This existing tag has a new event name (media_inactivity) added for the Tcl script to request notification of media inactivity detection.

Description

To enable/disable certain feature events to be intercepted by the script

Syntax

Infotag set evt_feature_report {["no_"]event_names}

Where event_name is a list of application event names that define what events should or should not be reported to application when call is active (connected). An event name with "no_" prefix means not to report it.

Mode

Write

Scope

ev_feature

Return Type

None

Direct Mapping

None

Event Names:

fax

modem

modem_phase

hookflash

onhook

offhook

media_inactivity

Example

The following example enables hookflash and disable fax and modem feature events to be received by the script:

infotag set evt_feature_report hookflash nofax no modem

The following example enables media_inactivity event to be received by the script:

infotag set evt_feature_report media_inactivity

evt_feature_type

This existing information tag adds two new event feature types representing media inactivity notification and media activity notification. Note that the script only needs to request for report type media_inactivity. However, after media inactivity is reported and the VoIP RTP starts receiving RTP/RTCP packets again, the event with type media_activity is automatically notified, indicating that the call is back alive.

Description

To return the feature type string when a feature event is received

Syntax

infotag get evt_feature_type

Mode

Read

Scope

ev_feature

Return Type

String

Direct Mapping

None

Event Names

fax

modem

modem_phase

hookflash

onhook

offhook

media_inactivity

media_activity

evt_feature_param

This is a new information tag added so that the Tcl application can pass along parameters related to the feature back to the script. The Media Inactive Call Detection feature uses this new tag to pass the information on whether RTCP packet has been received before the media inactive condition is met.

Mode

Scope

Return Type

Direct Mapping

Event Parameter

no media received-Media inactivity detected (no RTP or RTCP packets have been received for a configured amount of time). RTCP packet has been received before media inactivity condition is met.

no control info received-Media inactivity detected (no RTP or RTCP packets have been received for a configured amount of time). No RTCP packet has been received before media inactivity condition is met.

Example

infotag get evt_feature_param media_inactivity_type

media_timer_factor

This new information tag gives the Tcl script the ability to overwrite the configured gateway receive-rtcp timer. This value is used to calculate the timeout value used to detect media inactivity.

Description

To set the timer receive-rtcp timer. This new value is used within the scope of the script. It does not change the gateway configuration.

Syntax:

infotag set media_timer_factor timer_factor

Mode

Write

Scope

None

Return Type

None

Direct Mapping

None

Timer factor:

An integer between 2 and 1000. This value is the multiple of RTCP report transmission interval-a value of 5 is recommended.

Example:

infotag set media_timer_factor 6

Note:

If the value specified is not between 2 and 1000, the script generates an error message.

media_inactivity_err

The internal error code used by the Tcl script for this feature is media_inactivity_err (common IEC error #8). This IEC is used to disconnect a call where media inactivity is detected and reported.

Configuring Media Inactive Call Detection

This feature is enabled using Tcl IVR 2.0.

This section describes the use of this feature to set parameters for determining call inactive status and then clearing specific calls. These new options are designed to work as filters.

SUMMARY STEPS

enable

Make a call using the Tcl IVR 2.0 script application. While the call is going, the commands in steps 3 and 4 can be used.